Re: [PATCH 1/2] x86/math-emu: Add support for FCMOVcc and F[U]COMI[P] insns

[Denys Vlasenko <dvlasenk@redhat.com>]

[-- Attachment #1: Type: text/plain, Size: 411 bytes --]

On 09/16/2015 09:48 PM, Denys Vlasenko wrote:
> Run-tested by booting with "no387 nofxsr" and running test programs:
> 
> # ./test_FCMOV
> [RUN]	Testing fcmovCC instructions
> [OK]	fcmovCC
> # ./test_FCOMI
> [RUN]	Testing f[u]comi[p] instructions
> [OK]	f[u]comi[p]

The sources for these test programs are in this email.

Ingo, let me know if you want a patch which adds them
to tools/testing/selftests/x86/*


[-- Attachment #2: test_FCMOV.c --]
[-- Type: text/x-csrc, Size: 2101 bytes --]

#undef _GNU_SOURCE
#define _GNU_SOURCE 1
#undef __USE_GNU
#define __USE_GNU 1
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <signal.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/select.h>
#include <sys/time.h>
//#include <sys/ptrace.h>
#include <sys/wait.h>

#define TEST(insn) \
long double __attribute__((noinline)) insn(long flags) \
{						\
	long double out;			\
	asm ("\n"				\
	"	push	%1""\n"			\
	"	popf""\n"			\
	"	fldpi""\n"			\
	"	fld1""\n"			\
 	"	" #insn " %%st(1), %%st" "\n"	\
 	"	ffree	%%st(1)" "\n"		\
	: "=t" (out)				\
	: "r" (flags)				\
	);					\
	return out;				\
}

TEST(fcmovb)
TEST(fcmove)
TEST(fcmovbe)
TEST(fcmovu)
TEST(fcmovnb)
TEST(fcmovne)
TEST(fcmovnbe)
TEST(fcmovnu)

enum {
	CF = 1 << 0,
	PF = 1 << 2,
	ZF = 1 << 6,
};

int main(int argc, char **argv, char **envp)
{
	int err = 0;

	printf("[RUN]\tTesting fcmovCC instructions\n");
	/* If fcmovCC() returns 1.0, the move wasn't done */
	err |= !(fcmovb(0)   == 1.0); err |= !(fcmovnb(0)  != 1.0);
	err |= !(fcmove(0)   == 1.0); err |= !(fcmovne(0)  != 1.0);
	err |= !(fcmovbe(0)  == 1.0); err |= !(fcmovnbe(0) != 1.0);
	err |= !(fcmovu(0)   == 1.0); err |= !(fcmovnu(0)  != 1.0);

	err |= !(fcmovb(CF)  != 1.0); err |= !(fcmovnb(CF)  == 1.0);
	err |= !(fcmove(CF)  == 1.0); err |= !(fcmovne(CF)  != 1.0);
	err |= !(fcmovbe(CF) != 1.0); err |= !(fcmovnbe(CF) == 1.0);
	err |= !(fcmovu(CF)  == 1.0); err |= !(fcmovnu(CF)  != 1.0);

	err |= !(fcmovb(ZF)  == 1.0); err |= !(fcmovnb(ZF)  != 1.0);
	err |= !(fcmove(ZF)  != 1.0); err |= !(fcmovne(ZF)  == 1.0);
	err |= !(fcmovbe(ZF) != 1.0); err |= !(fcmovnbe(ZF) == 1.0);
	err |= !(fcmovu(ZF)  == 1.0); err |= !(fcmovnu(ZF)  != 1.0);

	err |= !(fcmovb(PF)  == 1.0); err |= !(fcmovnb(PF)  != 1.0);
	err |= !(fcmove(PF)  == 1.0); err |= !(fcmovne(PF)  != 1.0);
	err |= !(fcmovbe(PF) == 1.0); err |= !(fcmovnbe(PF) != 1.0);
	err |= !(fcmovu(PF)  != 1.0); err |= !(fcmovnu(PF)  == 1.0);

        if (!err)
                printf("[OK]\tfcmovCC\n");
	else
		printf("[FAIL]\tfcmovCC errors: %d\n", err);

	return err;
}

[-- Attachment #3: test_FCOMI.c --]
[-- Type: text/x-csrc, Size: 7121 bytes --]

#undef _GNU_SOURCE
#define _GNU_SOURCE 1
#undef __USE_GNU
#define __USE_GNU 1
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <signal.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/select.h>
#include <sys/time.h>
//#include <sys/ptrace.h>
#include <sys/wait.h>
#include <fenv.h>

enum {
	CF = 1 << 0,
	PF = 1 << 2,
	ZF = 1 << 6,
	ARITH = CF | PF | ZF,
};

long res_fcomi_pi_1;
long res_fcomi_1_pi;
long res_fcomi_1_1;
long res_fcomi_nan_1;
/* sNaN is s|111 1111 1|1xx xxxx xxxx xxxx xxxx xxxx */
/* qNaN is s|111 1111 1|0xx xxxx xxxx xxxx xxxx xxxx (some x must be nonzero) */
int snan = 0x7fc11111;
int qnan = 0x7f811111;
unsigned short snan1[5];
/* sNaN80 is s|111 1111 1111 1111 |10xx xx...xx (some x must be nonzero) */
unsigned short snan80[5] = { 0x1111, 0x1111, 0x1111, 0x8111, 0x7fff };

int test(long flags)
{
	feclearexcept(FE_DIVBYZERO|FE_INEXACT|FE_INVALID|FE_OVERFLOW|FE_UNDERFLOW);

	asm ("\n"

	"	push	%0""\n"
	"	popf""\n"
	"	fld1""\n"
	"	fldpi""\n"
 	"	fcomi	%%st(1), %%st" "\n"
 	"	ffree	%%st(0)" "\n"
 	"	ffree	%%st(1)" "\n"
	"	pushf""\n"
	"	pop	res_fcomi_1_pi""\n"

	"	push	%0""\n"
	"	popf""\n"
	"	fldpi""\n"
	"	fld1""\n"
 	"	fcomi	%%st(1), %%st" "\n"
 	"	ffree	%%st(0)" "\n"
 	"	ffree	%%st(1)" "\n"
	"	pushf""\n"
	"	pop	res_fcomi_pi_1""\n"

	"	push	%0""\n"
	"	popf""\n"
	"	fld1""\n"
	"	fld1""\n"
 	"	fcomi	%%st(1), %%st" "\n"
 	"	ffree	%%st(0)" "\n"
 	"	ffree	%%st(1)" "\n"
	"	pushf""\n"
	"	pop	res_fcomi_1_1""\n"
	:
	: "r" (flags)
	);
	if ((res_fcomi_1_pi & ARITH) != (0)) {
		printf("[BAD]\tfcomi_1_pi with flags:%lx\n", flags);
		return 1;
	}
	if ((res_fcomi_pi_1 & ARITH) != (CF)) {
		printf("[BAD]\tfcomi_pi_1 with flags:%lx->%lx\n", flags, res_fcomi_pi_1 & ARITH);
		return 1;
	}
	if ((res_fcomi_1_1 & ARITH) != (ZF)) {
		printf("[BAD]\tfcomi_1_1 with flags:%lx\n", flags);
		return 1;
	}
	if (fetestexcept(FE_INVALID) != 0) {
		printf("[BAD]\tFE_INVALID is set in %s\n", __func__);
		return 1;
	}
	return 0;
}

int test_qnan(long flags)
{
	feclearexcept(FE_DIVBYZERO|FE_INEXACT|FE_INVALID|FE_OVERFLOW|FE_UNDERFLOW);

	asm ("\n"
	"	push	%0""\n"
	"	popf""\n"
	"	flds	qnan""\n"
	"	fld1""\n"
	"	fnclex""\n"		// fld of a qnan raised FE_INVALID, clear it
 	"	fcomi	%%st(1), %%st" "\n"
 	"	ffree	%%st(0)" "\n"
 	"	ffree	%%st(1)" "\n"
	"	pushf""\n"
	"	pop	res_fcomi_nan_1""\n"
	:
	: "r" (flags)
	);
	if ((res_fcomi_nan_1 & ARITH) != (ZF|CF|PF)) {
		printf("[BAD]\tfcomi_qnan_1 with flags:%lx\n", flags);
		return 1;
	}
	if (fetestexcept(FE_INVALID) != FE_INVALID) {
		printf("[BAD]\tFE_INVALID is not set in %s\n", __func__);
		return 1;
	}
	return 0;
}

int testu_qnan(long flags)
{
	feclearexcept(FE_DIVBYZERO|FE_INEXACT|FE_INVALID|FE_OVERFLOW|FE_UNDERFLOW);

	asm ("\n"
	"	push	%0""\n"
	"	popf""\n"
	"	flds	qnan""\n"
	"	fld1""\n"
	"	fnclex""\n"		// fld of a qnan raised FE_INVALID, clear it
 	"	fucomi	%%st(1), %%st" "\n"
 	"	ffree	%%st(0)" "\n"
 	"	ffree	%%st(1)" "\n"
	"	pushf""\n"
	"	pop	res_fcomi_nan_1""\n"
	:
	: "r" (flags)
	);
	if ((res_fcomi_nan_1 & ARITH) != (ZF|CF|PF)) {
		printf("[BAD]\tfcomi_qnan_1 with flags:%lx\n", flags);
		return 1;
	}
	if (fetestexcept(FE_INVALID) != 0) {
		printf("[BAD]\tFE_INVALID is set in %s\n", __func__);
		return 1;
	}
	return 0;
}

int testu_snan(long flags)
{
	feclearexcept(FE_DIVBYZERO|FE_INEXACT|FE_INVALID|FE_OVERFLOW|FE_UNDERFLOW);

	asm ("\n"
	"	push	%0""\n"
	"	popf""\n"
//	"	flds	snan""\n"	// WRONG, this will convert 32-bit fp snan to a *qnan* in 80-bit fp register!
//	"	fstpt	snan1""\n"	// if uncommented, it prints "snan1:7fff c111 1100 0000 0000" - c111, not 8111!
//	"	fnclex""\n"		// flds of a snan raised FE_INVALID, clear it
	"	fldt	snan80""\n"	// fldt never raise FE_INVALID
	"	fld1""\n"
 	"	fucomi	%%st(1), %%st" "\n"
 	"	ffree	%%st(0)" "\n"
 	"	ffree	%%st(1)" "\n"
	"	pushf""\n"
	"	pop	res_fcomi_nan_1""\n"
	:
	: "r" (flags)
	);
	if ((res_fcomi_nan_1 & ARITH) != (ZF|CF|PF)) {
		printf("[BAD]\tfcomi_qnan_1 with flags:%lx\n", flags);
		return 1;
	}
//	printf("snan:%x snan1:%04x %04x %04x %04x %04x\n", snan, snan1[4], snan1[3], snan1[2], snan1[1], snan1[0]);
	if (fetestexcept(FE_INVALID) != FE_INVALID) {
		printf("[BAD]\tFE_INVALID is not set in %s\n", __func__);
		return 1;
	}
	return 0;
}

int testp(long flags)
{
	feclearexcept(FE_DIVBYZERO|FE_INEXACT|FE_INVALID|FE_OVERFLOW|FE_UNDERFLOW);

	asm ("\n"

	"	push	%0""\n"
	"	popf""\n"
	"	fld1""\n"
	"	fldpi""\n"
 	"	fcomip	%%st(1), %%st" "\n"
 	"	ffree	%%st(0)" "\n"
	"	pushf""\n"
	"	pop	res_fcomi_1_pi""\n"

	"	push	%0""\n"
	"	popf""\n"
	"	fldpi""\n"
	"	fld1""\n"
 	"	fcomip	%%st(1), %%st" "\n"
 	"	ffree	%%st(0)" "\n"
	"	pushf""\n"
	"	pop	res_fcomi_pi_1""\n"

	"	push	%0""\n"
	"	popf""\n"
	"	fld1""\n"
	"	fld1""\n"
 	"	fcomip	%%st(1), %%st" "\n"
 	"	ffree	%%st(0)" "\n"
	"	pushf""\n"
	"	pop	res_fcomi_1_1""\n"
	:
	: "r" (flags)
	);
	if ((res_fcomi_1_pi & ARITH) != (0)) {
		printf("[BAD]\tfcomi_1_pi with flags:%lx\n", flags);
		return 1;
	}
	if ((res_fcomi_pi_1 & ARITH) != (CF)) {
		printf("[BAD]\tfcomi_pi_1 with flags:%lx->%lx\n", flags, res_fcomi_pi_1 & ARITH);
		return 1;
	}
	if ((res_fcomi_1_1 & ARITH) != (ZF)) {
		printf("[BAD]\tfcomi_1_1 with flags:%lx\n", flags);
		return 1;
	}
	if (fetestexcept(FE_INVALID) != 0) {
		printf("[BAD]\tFE_INVALID is set in %s\n", __func__);
		return 1;
	}
	return 0;
}

int testp_qnan(long flags)
{
	feclearexcept(FE_DIVBYZERO|FE_INEXACT|FE_INVALID|FE_OVERFLOW|FE_UNDERFLOW);

	asm ("\n"
	"	push	%0""\n"
	"	popf""\n"
	"	flds	qnan""\n"
	"	fld1""\n"
	"	fnclex""\n"		// fld of a qnan raised FE_INVALID, clear it
 	"	fcomip	%%st(1), %%st" "\n"
 	"	ffree	%%st(0)" "\n"
	"	pushf""\n"
	"	pop	res_fcomi_nan_1""\n"
	:
	: "r" (flags)
	);
	if ((res_fcomi_nan_1 & ARITH) != (ZF|CF|PF)) {
		printf("[BAD]\tfcomi_qnan_1 with flags:%lx\n", flags);
		return 1;
	}
	if (fetestexcept(FE_INVALID) != FE_INVALID) {
		printf("[BAD]\tFE_INVALID is not set in %s\n", __func__);
		return 1;
	}
	return 0;
}

int testup_qnan(long flags)
{
	feclearexcept(FE_DIVBYZERO|FE_INEXACT|FE_INVALID|FE_OVERFLOW|FE_UNDERFLOW);

	asm ("\n"
	"	push	%0""\n"
	"	popf""\n"
	"	flds	qnan""\n"
	"	fld1""\n"
	"	fnclex""\n"		// fld of a qnan raised FE_INVALID, clear it
 	"	fucomip	%%st(1), %%st" "\n"
 	"	ffree	%%st(0)" "\n"
	"	pushf""\n"
	"	pop	res_fcomi_nan_1""\n"
	:
	: "r" (flags)
	);
	if ((res_fcomi_nan_1 & ARITH) != (ZF|CF|PF)) {
		printf("[BAD]\tfcomi_qnan_1 with flags:%lx\n", flags);
		return 1;
	}
	if (fetestexcept(FE_INVALID) != 0) {
		printf("[BAD]\tFE_INVALID is set in %s\n", __func__);
		return 1;
	}
	return 0;
}

int main(int argc, char **argv, char **envp)
{
	int err = 0;

        printf("[RUN]\tTesting f[u]comi[p] instructions\n");
	err |= test(0);
	err |= test_qnan(0);
	err |= testu_qnan(0);
	err |= testu_snan(0);
	err |= test(CF|ZF|PF);
	err |= test_qnan(CF|ZF|PF);
	err |= testu_qnan(CF|ZF|PF);
	err |= testu_snan(CF|ZF|PF);
	err |= testp(0);
	err |= testp_qnan(0);
	err |= testup_qnan(0);
	err |= testp(CF|ZF|PF);
	err |= testp_qnan(CF|ZF|PF);
	err |= testup_qnan(CF|ZF|PF);
	if (!err)
		printf("[OK]\tf[u]comi[p]\n");
	else
		printf("[FAIL]\tf[u]comi[p] errors: %d\n", err);

	return err;
}